<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<div id="app">
<!--  1，直接拼接 : 太麻烦 直接排除  -->
  <h2>{{firstName}} {{lastName}}</h2>
<!--  2，通过定义methods-->
  <h2>{{getFullName()}}</h2>
  <h2>{{getFullName()}}</h2>
  <h2>{{getFullName()}}</h2>
  <h2>{{getFullName()}}</h2>
  <h2>{{getFullName()}}</h2>
<!--  3，通过computed-->
  <h2>{{fullName}}</h2>
  <h2>{{fullName}}</h2>
  <h2>{{fullName}}</h2>
  <h2>{{fullName}}</h2>
  <h2>{{fullName}}</h2>
</div>

<script src="./js/vue.js"></script>

<script>
  const app = new Vue({
    el:'#app',
    data:{
      message:'Hello World',
      firstName:'Kobe',
      lastName:'Bryant'
    },
    methods:{
      getFullName:function(){
        console.log('getFullName'); //看调用了几次
        return this.firstName + ' ' + this.lastName;
      }
    },
    computed:{
      fullName:function(){
        console.log('fullName'); // 看调用了几次
        return this.firstName + ' ' + this.lastName;
      }
    }
  });
</script>
</body>
</html>